Wind and light storage and charging micro-grid system for providing high-quality power supply

Abstract

The invention relates to a wind and light storage and charging micro-grid system for providing high-quality power supply. The system comprises a wind power generation system, a photovoltaic power generation system, an energy storage system, a charging pile, a multi-port power electronic conversion device, a safety fault detection protection device, a broadband disturbance resisting converter and an energy coordination controller. Through a multi-port power electronic conversion device oriented to a low-carbon park scene, a corresponding equipment-level coordination control strategy and an inter-port energy management strategy, the influence of broadband disturbance on the performance and stability of a micro-grid system is suppressed; the self-adaptive remodeling of the equipment port damping is carried out within the achievable range, and the broadband interaction between the equipment of the micro-grid system is inhibited, so that the stable supply of energy is realized, the load of the power grid is effectively balanced, and the energy utilization efficiency and the power supply quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microgrids, and in particular to a wind-solar-storage-charging microgrid system that provides high-quality power supply. Background Art

[0002] In 2021, my country proposed the "dual carbon target" to build a new power system, and the transformation of energy development from centralized and extensive to distributed, intensive, efficient and green has been accelerated again. The "Guiding Opinions on Energy Work in 2022" issued by the National Energy Administration proposed that in 2022, the proportion of wind power and photovoltaic power generation in my country's total electricity consumption will reach about 12.2%. It also requires the promotion of the coordinated development of smart energy such as distributed energy, microgrids, and multi-energy complementarity with smart cities and parks.

[0003] Data shows that there are more than 20,000 industrial parks in my country, which are important carriers of my country's industrial development. But it is also because of this that industrial parks have become the country's largest carbon emitters. Low-carbon parks take low-carbon operation as their core concept, widely integrate new energy and digital technologies, and are committed to improving the environmental friendliness and operation level of park energy use. In terms of implementation structure, low-carbon parks have introduced a large number of green, distributed power sources and power supply forms such as "photovoltaic storage direct and flexible", and therefore widely connected various types of power electronic converters for multiple links such as generation, transformation, distribution, and use.

[0004] However, the characteristics of distributed power sources and loads, such as strong volatility and wideband susceptibility to disturbance, are intertwined with the complex impedance characteristics of the cable distribution network, and are coupled with each other, often causing a series of problems such as voltage fluctuations, wideband harmonics, and even harmonic amplification. These problems will affect the normal and stable operation of grid-connected converters, start-end protection equipment, etc. within a wide frequency range, and thus threaten the overall power supply quality and reliability of the park.

[0005] Therefore, it is necessary to combine the unique characteristics of the low-carbon park power supply system, carry out optimization design from the key equipment and system levels, solve the key problems affecting its operating performance and reliability, and build high-quality power supply technology suitable for low-carbon parks. This is the necessary technical guarantee for promoting the high-level and long-term development of low-carbon parks. Summary of the invention

[0006] In view of the above problems existing in the prior art, the present invention is proposed.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a wind, solar, storage and charging microgrid system that provides high-quality power supply, including: a wind power generation system, a photovoltaic power generation system, an energy storage port, a charging pile and a multi-port power electronic conversion device, a safety fault detection and protection device, a broadband disturbance protection inverter and an energy coordination controller.

[0008] As a preferred solution of the wind-solar-storage-charging microgrid system providing high-quality power supply described in the present invention, the wind power generation system, photovoltaic power generation system, energy storage port and charging piles and multiple energy forms must be simultaneously connected to a multi-port power electronic conversion device to achieve flexible conversion and utilization of AC / DC power.

[0009] As a preferred solution of a wind-solar-storage-charging microgrid system providing high-quality power supply described in the present invention, wherein: the multi-port power electronic conversion device comprises a plurality of photovoltaic DC / DC converter modules, energy storage DC / DC converter modules and grid-connected DC / AC bidirectional converter modules connected in parallel;

[0010] The DC output terminals of all converter modules are connected in parallel to the DC750V DC bus.

[0011] As a preferred solution of a wind-solar-storage-charging microgrid system providing high-quality power supply as described in the present invention, the AC port of the multi-port power electronic conversion device is connected to the park distribution room to supply power to the park AC load or to charge the energy storage battery; the voltage level of the distribution room is 380VAC.

[0012] As a preferred solution of a wind-solar-storage-charging microgrid system providing high-quality power supply as described in the present invention, wherein: the AC port of the multi-port power electronic conversion device has power coordination control and network control functions; the energy storage port has charging and discharging power control, current limiting characteristics, and voltage limiting characteristics; the photovoltaic port has maximum power tracking and power limiting functions; the charging pile port can receive instructions from the charging pile in real time to realize automatic distribution of charging power.

[0013] As a preferred solution of a wind-solar-storage-charging microgrid system providing high-quality power supply as described in the present invention, the photovoltaic power generation system includes photovoltaic cells, a junction box and a photovoltaic DC / DC converter module; the photovoltaic cells are flexibly installed on the roof of a park building, a park carport, and a glass curtain wall, and are connected to the photovoltaic DC / DC converter module in a multi-port power electronic conversion device through a junction box.

[0014] As a preferred solution of a wind-solar-storage-charging microgrid system providing high-quality power supply described in the present invention, the energy storage port includes a lithium iron phosphate energy storage battery pack, a battery management system BMS and an energy storage DC / DC converter module. The lithium iron phosphate energy storage battery is installed in a separate cabinet and connected to the energy storage DC / DC converter module in a multi-port power electronic conversion device through the BMS. The power for charging the energy storage battery is provided by the photovoltaic power generation system, the wind power generation system or the AC port of the multi-port power electronic conversion device.

[0015] As a preferred solution of a wind-solar-storage-charging microgrid system that provides high-quality power supply as described in the present invention, the safety fault detection and protection device is used for accurate fault detection and protection under multi-source and load interference, and realizes DC leakage current detection, fault arc detection, fault feature extraction, linkage protection, operation indication, anti-electromagnetic interference, and coordinated communication with the outside for multi-port power electronic conversion devices.

[0016] As a preferred solution of the wind-solar-storage-charging microgrid system providing high-quality power supply described in the present invention, the broadband disturbance resistance converter is used to suppress various resonances of the microgrid system under complex working conditions of multiple energy access and multiple power loads, ensuring that the power quality of the system meets the national standard requirements.

[0017] As a preferred solution of the wind, solar, storage and charging microgrid system that provides high-quality power supply as described in the present invention, the scheduling and optimization management of the entire microgrid system are completed by the energy coordination controller and the supporting energy management software system, and the coordination control is completed by an energy management system that integrates operation monitoring, power scheduling, and coordination control functions, thereby realizing intelligent and balanced allocation of power among photovoltaics, energy storage, wind power, and charging piles.

[0018] Beneficial effects of the invention: The invention can improve the reliability and stability of the energy supply of the park. The microgrid system usually includes multiple power generation methods. The diversified energy combination reduces the dependence on traditional energy and increases the stability and reliability of energy supply. In the event of a power grid failure or special circumstances, the microgrid can operate independently and provide uninterrupted power supply to critical loads, thereby ensuring the normal operation of important equipment and the continuity of production.

[0019] The wind-solar-storage-charging microgrid system can flexibly adjust the power supply mode according to actual needs and optimize the energy distribution and utilization. For example, during periods of low electricity prices, the system can use the mains electricity to charge the energy storage equipment, and during periods of high electricity prices, the energy in the energy storage equipment is used to supply power, thereby reducing electricity costs. In addition, the use of energy storage equipment can also balance the difference between energy supply and demand and improve energy utilization efficiency.

[0020] Compared with traditional energy supply, which has the problems of centralized energy supply and long-distance transmission, microgrid technology can gradually push energy supply to the user end. This decentralized energy supply model can reduce transmission losses and grid congestion, and improve energy efficiency. At the same time, microgrid systems usually use renewable energy sources such as solar and wind power to generate electricity, reducing dependence on traditional fossil energy. This sustainable energy supply model helps reduce greenhouse gas emissions and environmental pollution, and promotes sustainable development of energy.

[0021] The wind, solar, storage and charging microgrid system is equipped with advanced sensing and measurement technology, equipment technology, control methods and decision support systems. The application of these technologies enables the system to monitor and control the production, storage and distribution of energy in real time, improving the intelligence and automation level of the system. In addition, the system can also realize functions such as remote monitoring and fault warning, further improving the reliability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0023] Figure 1 A first circuit schematic diagram of a wind-solar-storage-charging microgrid system providing high-quality power supply is provided for one embodiment of the present invention.

[0024] Figure 2 A second circuit diagram of a wind-solar-storage-charging microgrid system providing high-quality power supply is provided as an embodiment of the present invention.

[0025] Figure 3 A broadband disturbance-resistant converter topology diagram of a wind-solar-storage-charging microgrid system providing high-quality power supply is provided as an embodiment of the present invention.

[0026] Figure 4 A schematic diagram of an arc detection system for a wind-solar-storage-charging microgrid system providing high-quality power supply according to an embodiment of the present invention.

[0027] Figure 5 A schematic diagram of a new energy grid-building power generation technology for a wind, solar, storage and charging microgrid system that provides high-quality power supply, provided in accordance with an embodiment of the present invention.

[0028] Figure 6 A schematic diagram of the virtual synchronization technology of a wind-solar-storage-charging microgrid system providing high-quality power supply, provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0030] Example 1

[0031] Reference Figure 1-Figure 6 This is the first embodiment of the present invention, which provides a wind-solar-storage-charging microgrid system that provides high-quality power supply, including:

[0032] like Figure 1 The high-quality wind, solar, energy storage and charging microgrid system shown in the figure, including wind power generation system, photovoltaic power generation system, energy storage system, charging piles and other energy forms, must be centrally connected to a multi-port power electronic conversion device at the same time to achieve flexible conversion and utilization of AC / DC power.

[0033] The AC port of the multi-port power electronic converter is connected to the power distribution room in the park to supply power to the AC load in the park or to charge the energy storage battery. The voltage level of the power distribution room is 380VAC.

[0034] The multi-port power electronic conversion device includes multiple sets of photovoltaic DC / DC converter modules, energy storage DC / DC converter modules and grid-connected DC / AC bidirectional converter modules in parallel. The DC output terminals of all converter modules are connected in parallel to the DC750V DC bus.

[0035] The AC port of the multi-port power electronic conversion device has power coordination control and network control functions; the energy storage port has charging and discharging power control, current limiting characteristics, and voltage limiting characteristics; the photovoltaic port has maximum power tracking and power limiting functions; the charging pile port can receive instructions from the charging pile in real time to realize automatic distribution of charging power.

[0036] Power control condition 1: Dynamic capacity expansion: When the short-term load in the zero-carbon park exceeds the transformer capacity, the energy storage port can be controlled to discharge, and the AC port can be inverted and output to the park power grid to dynamically expand the transformer capacity and improve the power grid operation efficiency.

[0037] Power control condition 2: Peak shaving and valley filling: According to the prediction results of the park's source-load-storage synergy, the energy storage port charging and discharging curve is formulated. When the grid load is low, the energy storage port is charged to store the excess power in the park; when the grid load is high, the energy storage port is discharged to release the stored power to the park grid to relieve the grid load pressure.

[0038] Power control condition 3: Curve smoothing: Since renewable energy (wind power, photovoltaic) is greatly affected by weather and environment, its power output has large short-term fluctuations, which will pose a challenge to the stable operation of the power grid. Smoothing its power output curve helps improve the stability and reliability of the power grid. The volatility of renewable energy can be smoothed by dynamically adjusting the charging and discharging strategy of the energy storage port, making its output more stable.

[0039] Network control: The inverter or converter is controlled as a voltage source to have functions similar to traditional synchronous generators. This control method enables the device to independently or collaboratively provide voltage, frequency and phase support for the system like a generator. Virtual synchronization technology is used, and the filtered photovoltaic measured power is used as the synchronous machine power command to achieve inertia damping and smooth fluctuations.

[0040] The current limiting characteristics of the energy storage system are mainly reflected in its protection circuit, preventing overcurrent and short circuit, etc., ensuring that the energy storage system can remain safe and stable under normal operation and fault conditions.

[0041] The voltage limiting feature refers to the feature that during the operation of the energy storage system, the voltage is limited to a safe and reasonable range through certain control strategies and equipment to prevent excessively high or low voltage from causing damage to the equipment and system. When an abnormal system voltage is detected, the inverter can quickly adjust its output voltage to maintain the stability of the system voltage.

[0042] Furthermore, the principle diagram of network control function is as follows: Figure 5 As shown, virtual synchronization technology is adopted, and the filtered photovoltaic measured power is used as the synchronous machine power command to achieve inertia damping and smooth fluctuations.

[0043] Beneficial effects: The grid control function can smooth out the fluctuation of renewable energy power generation, reduce the peak load pressure of large power grids, and improve the acceptance level of large power grids for renewable energy.

[0044] Furthermore, the principle of virtual synchronization technology (VSG) is as follows Figure 6 As shown, in the topological structure, the converter is equivalent to a synchronous generator, the grid impedance is equivalent to the stator reactance, the DC source is equivalent to the prime mover, the output voltage is equivalent to the internal potential, and the output power is equivalent to the electromagnetic power.

[0045] Beneficial effects: VSG control can realize seamless switching between on-grid and off-grid, weak grid voltage support, and frequency and voltage regulation functions.

[0046] The photovoltaic power generation system includes: photovoltaic cells, combiner boxes and photovoltaic DC / DC converter modules.

[0047] Further, if Figure 2 The high-quality wind-solar-storage-charging microgrid system shown in the figure can be installed not only on the roof of the park building, but also flexibly in the park carport, glass curtain wall and other locations, and connected to the photovoltaic DC / DC converter module in the multi-port power electronic conversion device through the junction box.

[0048] The energy storage port includes a lithium iron phosphate energy storage battery pack, a battery management system BMS and an energy storage DC / DC converter module. The lithium iron phosphate energy storage battery is installed in a separate cabinet and connected to the energy storage DC / DC converter module in the multi-port power electronic conversion device through the BMS.

[0049] The electricity for charging the energy storage battery can be provided by a photovoltaic power generation system, a wind power generation system or an AC port of a multi-port power electronic conversion device.

[0050] The safety fault detection and protection device is used for accurate fault detection and protection under multi-source and load interference. It can realize DC leakage current detection, fault arc detection, fault feature extraction, linkage protection, operation indication, anti-electromagnetic interference, and coordinated communication with the outside for multi-port power electronic conversion devices.

[0051] Furthermore, the arc detection system topology is as follows Figure 4 As shown in the figure, it mainly includes the analog signal processing part and the digital signal processing part of the front end. The identification is carried out by combining the time domain and the frequency domain, and the FFT signal processing is performed on the current noise to obtain the amplitude-frequency characteristics of the current noise. The amplitude is integrated within the arc frequency domain, and the integral value is compared with its threshold value to accurately determine whether DC arcing has occurred.

[0052] Furthermore, the detection accuracy of the safety fault detection and protection device is not less than 95%, and the detection and protection time is not more than 20ms. It has DC leakage current detection, DC arc detection, DC short circuit fault detection and communication functions, and supports RS485-Modbus protocol.

[0053] The broadband disturbance protection converter adopts NPC three-level topology, such as Figure 3 As shown. The broadband disturbance protection converter is used to suppress various resonances of the microgrid system under complex working conditions with multiple energy sources and multiple power loads, ensuring that the power quality of the system meets the national standards.

[0054] Working condition 1: Low-frequency disturbances mainly occur in the power transmission converter on the source side. By reasonably setting the control parameters and relative relationships of DC voltage control, AC voltage control, and phase-locked loop, it is ensured that the system does not have the ability to transmit low-frequency disturbances in the low-frequency band. Specific measures include:

[0055] (1) Make the PI zero point of the DC voltage control DVC as far away from the phase-locked loop bandwidth frequency as possible;

[0056] (2) Make the AC voltage control AVC bandwidth much higher than the PLL bandwidth;

[0057] (3) For the phase-locked loop (PLL), a large P and small I tuning method should be adopted to minimize the phase lag introduced by the PLL.

[0058] Condition 2: When the harmonic frequency band disturbance occurs in the condition where the grid-side impedance is obvious (such as the grid-side capacitance value is obvious in the cable system), the harmonic frequency band disturbance will reduce the bandwidth of the equivalent current loop, causing the resonant controller used to control harmonics to appear outside the bandwidth, thus causing stability problems. In order to eliminate this effect, the vector resonant controller is phase corrected to compensate for the delay and avoid crossing -180° at the resonant frequency.

[0059] Working condition 3: High-frequency disturbances are mainly caused by passive components of the inverter. The first method to resist the risk of high-frequency disturbances is to reduce the control delay, that is, when the inverter uses inverter-side current feedback, ensure that the phase lag caused by the delay at the LCL resonant frequency is less than 90° and ensure a certain margin, so as to avoid the high-frequency resonance problem. Another method is to use an active damping solution to damp the high-frequency / ultra-high-frequency disturbance emission caused by the above passive components.

[0060] Furthermore, the broadband disturbance protection converter adopts a mid-point clamped NPC three-level topology, which has the characteristics of small AC and DC current harmonics, high power factor, small single-tube pressure, and high device stability.

[0061] Furthermore, the wideband disturbance protection converter can achieve adaptive protection against disturbances in the range of not less than 1kHz, and the harmonics of the current delivered to the grid or local AC load should not exceed 3%, and the DC current component should not exceed 0.5% of its output current rating. In off-grid operation mode, the output voltage deviation at rated output power does not exceed ±5% of the rated voltage, and the output voltage THD is not greater than 3%.

[0062] The dispatching and optimization management of the microgrid system is completed by the energy coordination controller and the supporting energy management software system. The coordination control is completed by the energy management system that integrates operation monitoring, power dispatching, coordination control and other functions. It realizes the intelligent and balanced allocation of power between photovoltaic, energy storage, wind power and charging piles.

[0063] Furthermore, the main control strategies of the energy coordination controller include:

[0064] (1) Photovoltaic and energy storage microgrid applications

[0065] Responsible for the management of each micro-source, controllable load and access point within the microgrid to achieve stable and economical operation of the entire microgrid. The controller uses local information (power source point, load point) to adjust and control the voltage and frequency of the microgrid. In the state transition mode (on-grid and off-grid switching), the smooth on-grid and off-grid switching is achieved by controlling each power source point and controllable load shedding. In steady-state operation, the controller provides the optimal operation of the system and maximizes the value of the microgrid.

[0066] (2) Peak shaving and valley filling control strategy

[0067] When the difference between peak and valley electricity prices is large, the profit target can be achieved by using energy storage to reduce peak loads and fill valleys according to the peak and valley electricity price difference of the time-of-use electricity price policy. Operators only need to set the corresponding energy storage battery charging and discharging time according to the specific time of the local peak, valley and flat electricity prices to obtain profits.

[0068] During valley price period, the energy storage is charged; during peak price period, the energy storage is discharged, otherwise the energy storage is on standby. The user is supported to configure the peak shaving and valley filling time.

[0069] (3) Load following control

[0070] Track the load power consumption curve and adjust the charging and discharging power and time according to the load conditions. Automatically increase the discharge power or reduce the charging power when the load power increases.

[0071] Supports users to set power limit value. When the limit value is exceeded, the discharge power will be automatically increased or the charging power will be reduced. Otherwise, the operating status will remain unchanged.

[0072] (4) Hill climbing control

[0073] The charging and discharging power of the energy storage battery is used to smooth the power fluctuation of the photovoltaic power generation system, so that the output power fluctuation is as close to the specified range as possible; at the same time, the battery life model is taken into consideration, the SOC feedback factor is added, and the target climbing slope is adjusted according to the current SOC value.

[0074] (5) Power smoothing

[0075] The user sets the output power of the AC port, and the output power is smoothly stabilized at the set power through the charging and discharging of the energy storage battery. Under this control strategy, the energy storage port will frequently adjust the charging and discharging power, which has a greater impact on the life of the energy storage port, but the power fluctuation of the AC port is relatively small.

[0076] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0077] Embodiment 2, the second embodiment of the present invention, is different from the previous embodiment in that:

[0078] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0079] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0080] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0081] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

Claims

1. A wind-solar-storage-charging microgrid system that provides high-quality power supply, characterized by: include, Wind power generation systems, photovoltaic power generation systems, energy storage ports, charging piles and multi-port power electronic conversion devices, safety fault detection and protection devices, broadband disturbance protection converters and energy coordination controllers.

2. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 1, characterized in that: The wind power generation system, photovoltaic power generation system, energy storage port and charging piles must be centrally connected to a multi-port power electronic conversion device at the same time to achieve flexible conversion and utilization of AC / DC power.

3. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 2, characterized in that: The multi-port power electronic conversion device comprises a plurality of photovoltaic DC / DC converter modules, energy storage DC / DC converter modules and grid-connected DC / AC bidirectional converter modules connected in parallel; The DC output terminals of all converter modules are connected in parallel to the DC750V DC bus.

4. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 2, characterized in that: The AC port of the multi-port power electronic conversion device is connected to the park distribution room to supply power to the park AC load or to charge the energy storage battery; the voltage level of the distribution room is 380VAC.

5. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 2, characterized in that: The AC port of the multi-port power electronic conversion device has power coordination control and network control functions; the energy storage port has charging and discharging power control, current limiting characteristics, and voltage limiting characteristics; the photovoltaic port has maximum power tracking and power limiting functions; the charging pile port can receive instructions from the charging pile in real time to realize automatic distribution of charging power.

6. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 1, characterized in that: The photovoltaic power generation system includes photovoltaic cells, a junction box and a photovoltaic DC / DC converter module; the photovoltaic cells are flexibly installed on the roof of a park building, a park carport, and a glass curtain wall, and are connected to the photovoltaic DC / DC converter module in a multi-port power electronic conversion device through the junction box.

7. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 1, characterized in that: The energy storage port includes a lithium iron phosphate energy storage battery pack, a battery management system BMS and an energy storage DC / DC converter module. The lithium iron phosphate energy storage battery is installed in a separate cabinet and is connected to the energy storage DC / DC converter module in a multi-port power electronic conversion device through the BMS. The power for charging the energy storage battery is provided by a photovoltaic power generation system, a wind power generation system or an AC port of a multi-port power electronic conversion device.

8. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 1 or 4, characterized in that: The safety fault detection and protection device is used for accurate fault detection and protection under multi-source and load interference, and realizes DC leakage current detection, fault arc detection, fault feature extraction, linkage protection, operation indication, anti-electromagnetic interference, and coordinated communication with the outside for multi-port power electronic conversion devices.

9. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 1, characterized in that: The broadband disturbance protection converter is used to suppress various resonances of the microgrid system under complex working conditions with multiple energy sources connected and multiple power loads.

10. A wind-solar-storage-charging microgrid system providing high-quality power supply as claimed in claim 1, characterized in that: The dispatching and optimization management of the entire microgrid system are completed by the energy coordination controller and the supporting energy management software system. The coordination control is completed by the energy management system that integrates operation monitoring, power dispatching and coordination control functions, realizing the intelligent and balanced allocation of power among photovoltaic, energy storage, wind power and charging piles.

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